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Wave Propagation Group Research & Development Activities

OCEAN ACOUSTIC TOMOGRAPHY

Ocean acoustic travel-time tomography was introduced by Munk and Wunsch in 1979 as a remote-sensing technique for monitoring the spatial and temporal variability of oceanographic parameters (mainly temperature and currents) in the large scale. Measuring the travel times of pulsed acoustic signals propagating through the water mass over a multitude of different paths, and exploiting the knowledge about how travel times are affected by the ocean state, the latter can be obtained by inversion. Low-frequency sound propagates efficiently over long distances of thousands of kilometers and thus ocean acoustic tomography can be used to monitor large sea areas, from the mesoscale to the basin and global scale.

http://www.iacm.forth.gr/wave/images/t1.jpg

http://www.iacm.forth.gr/wave/images/t2.jpg

http://www.iacm.forth.gr/wave/images/t3.jpg

Left: Evolution of average temperature profile along a 600-km section in the Western Mediterranean (from biweekly hydrographic surveys). Middle: Evolution of measured acoustic travel times along the section (tomographic data). Right: Evolution of retrieved temperature profiles by inversion of travel time data (tomographic results).

 

IACM contributions

IACM's Wave Propagation Group is active in the field of ocean acoustic tomography since the early 90's focusing on the development of enhanced analysis methods for tomographic data, based on wave-theoretic propagation modeling, with contributions in the following directions

  • Wave-theoretic modeling of tomographic observables
  • Sensitivity kernels of underwater acoustic travel times
  • Adaptive non-linear inversion methods
  • Statistical identification and inversion schemes
  • Automation of tomography data analysis
  • Data analysis of large-scale tomography experiments
  • Matched-field processing

Related Publications

  • E.K. Skarsoulis, B.D. Cornuelle, M.A. Dzieciuch, Long-range asymptotic behavior of vertical travel-time sensitivity kernels, Journal of the Acoustical Society of America, in print, 2013.
  • E.K. Skarsoulis, B.D. Cornuelle, M.A. Dzieciuch, Second-order sensitivity of acoustic travel times to sound-speed perturbations, Acta Acustica, Vol. 97, pp. 533-543, 2011.
  • S.Sandven, H.Sagen, L.Bertino, A Beszczynska-Möller, E.Fahrbach, P.F.Worcester, M.A.Dzieciuch, W.Walczowski, P.Wieczorek, E.Skarsoulis, A.Morozov, D.Dumont, C.Lee, B.D.Dushaw, E.Hansen, H.Rohr, The Fram Strait integrated ocean observing and modelling system, Proc. 6th EUROGOOS Conf., Sopot,  2011.
  • E. Skarsoulis, G. Piperakis, M. Kalogerakis, H. Sagen, S. Haugen, A. Beszczynska-Moeller, P. Worcester, Tomographic inversions from the Fram Strait 2008-9 experiment, Proc. 10h Eur. Conf. Underwater Acoustics, Constantinople, 2010.
  • E.K. Skarsoulis, B.D. Cornuelle, M.A. Dzieciuch, Travel-time sensitivity kernels in long-range propagation, Journal of the Acoustical Society of America, Vol. 126, pp. 2223-2233, 2009.
  • E.K. Skarsoulis, G.S. Piperakis, Use of acoustic navigation signals for simultaneous localization and sound-speed estimation, Journal of the Acoustical Society of America, Vol. 125, pp. 1384-1393, 2009.
  • H. Sagen, S. Sandven, A. Beszczynska-Moeller, O. Boebel, T. Duda, L. Freitag, J.C. Gascard, A. Gavrilov, C. Lee, D. Mellinger, P. Mikhalevsky, S. Moore, A. Morozov, M. Rixen, E. Skarsoulis, K. Stafford, E. Tveit, P. Worcester, Acoustic technologies for observing the interior of the Arctic Ocean, Proc. Oceanobs'09, Venice, 2009.
  • B. Dushaw, W. Au , A. Beszczynska-Moeller, R. Brainard, B. Cornuelle, T. Duda, M. Dzieciuch, A. Forbes, L. Freitag, J.C. Gascard, A. Gavrilov, J. Gould, B. Howe, S. Jayne, O. Johannessen, J. Lynch, D. Martin, D. Menemenlis, P. Mikhalevsky, J. Miller, S. Moore, W. Munk, J. Nystuen, R. Odom, J. Orcutt, T. Rossby, H. Sagen, S. Sandven, J. Simmen, E. Skarsoulis, B. Southall, K. Stafford, R. Stephen, K. Vigness-Raposa, S. Vinogradov, K. Wong, P. Worcester, C. Wunsch, A global ocean acoustic observing network, Community White Paper, Proc. Oceanobs'09, Venice, 2009.
  • E. Skarsoulis, G. Piperakis, M. Kalogerakis, H. Sagen, Ocean acoustic tomography: Travel-time inversion in the eastern Fram Strait, Proc. 9h Eur. Conf. Underwater Acoustics, M. Zakharia (Ed.), pp. 19-23, 2008.
  • T. Avsic, U. Send, E.K. Skarsoulis, Six years of tomography observation in the central Labrador sea, Proc. Int. Conf. Underwater Acoustic Measurements: Technologies & Results, Heraklion  2005.
  • G.N. Makrakis, E.K. Skarsoulis, Asymptotic approximation of ocean-acoustic pulse propagation in the time domain, Journal of Computational Acoustics, Vol. 12, pp. 197-216, 2004.
  • E.K. Skarsoulis B.D. Cornuelle, Travel-time sensitivity kernels in ocean acoustic tomography, Journal of the Acoustical Society of America, Vol. 116, pp. 227-238, 2004.
  • E.K. Skarsoulis, U. Send, G. Piperakis, P. Testor, Acoustic thermometry of the western Mediterranean basin, Journal of the Acoustical Society of America, Vol. 116, pp. 790-798, 2004.
  • E.K. Skarsoulis, Waveform perturbation of tomographic receptions due to sound-speed variations, Acta Acoustica, Vol. 89, pp. 789-798, 2003.
  • E.K. Skarsoulis, Multi-section matched-peak tomographic inversion with a moving source, Journal of the Acoustical Society of America, Vol. 110, pp. 786-797, 2001.
  • D. Kindler, U. Send, E.K. Skarsoulis, Relative-time inversions in the Labrador Sea acoustic tomography experiment, Acta Acoustica, Vol. 87, pp. 738-747, 2001.
  • M.I. Taroudakis and M.G. Markaki, Tomographic inversions in shallow water using modal travel time measurements, Acta Acoustica, Vol 87, pp 647-658, 2001.
  • E.K. Skarsoulis, U. Send, One-step analysis of non-linear traveltime data in ocean acoustic tomography, Journal of Atmospheric and Oceanic Technology, Vol. 17, pp. 240-254, 2000.
  • E.K. Skarsoulis, A matched-peak inversion approach for ocean acoustic travel-time tomography, Journal of the Acoustical Society of America, Vol. 107, pp. 1324-1332, 2000.
  • E.K. Skarsoulis, G.A. Athanassoulis, Second-order perturbations of peak arrival times due to sound speed variations, Journal of the Acoustical Society of America, Vol. 104, pp. 3313-3325, 1998.
  • U. Send, G. Krahmann, D. Mauuary, Y. Desaubies, F. Gaillard, T. Terre, J. Papadakis, M. Taroudakis, E. Skarsoulis, and C. Millot, Acoustic observations of heat content across the Mediterranean Sea, Nature, Vol. 385, pp. 615-617, 1997
  • M.I. Taroudakis and M.G. Markaki, On the use of matched-field processing and hybrid algorithms for vertical slice tomography, Journal of the Acoustical Society of America, Vol 102, pp 885-895, 1997.
  • E.K. Skarsoulis, G.A. Athanassoulis, U. Send, Ocean acoustic tomography based on peak arrivals, Journal of the Acoustical Society of America, Vol. 100, pp. 797-813, 1996.
  • G.A. Athanassoulis, E.K. Skarsoulis, Arrival-time perturbations of broadband tomographic signals due to sound-speed disturbances. A wave theoretic approach, Journal of the Acoustical Society of America, Vol. 97, pp. 3575-3588, 1995.
  • The THETIS Group, Open-ocean deep convection explored in the Mediterranean, EOS Transactions of the American Geophysical Union, Vol. 75, No 19, pp. 217-221, 1994.
  • M.I. Taroudakis and J.S. Papadakis, Modal inversion schemes for ocean acoustic tomography, Journal of Computational Acoustics, Vol. 1, No 4, pp 395-421, 1993.

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